The present invention relates to a water polluting phytoplankton drifts collecting device, and more particularly to a water polluting phytoplankton drift collecting device, which collects water polluting phytoplankton drifts and dormant spores thereof vegetating in dead water areas like lakes and marshes, to prevent them from proliferating in such water areas to cause the pollution thereof, thereby improving the water cleanliness there.
In water areas, such as lakes and marshes or dams, it has frequently been reported that the movements of the water are stagnant and tend to be subject to supernutrition due to the change recently seen in the life style of people living therearound and the extraordinary proliferation of phytoplankton. Such extraordinary proliferation of phytoplankton not only mars the appearance of the water areas but also hinders branchial respiration of fishes and causes living things in the lower water layers to perish due to the lack of oxygen there and invites the deterioration of the water quality which can result in a musty smell in tap water.
Conventionally, there have been proposed a variety of measures to prevent the proliferation of phytoplankton including (1) a method of preventing the proliferation of the water polluting phytoplankton by removing nutritious substances by means of phosphorus (P) or nitrogen (N) compounds, silica (SiO.sub.2), or the like; (2) a method of killing the phytoplankton by use of algicides, such as copper sulfate, chlorine (Cl.sub.2) or the like; and (3) an air pumping pipe method to forcibly circulate the dead water by use of an air pumping pipe to increase the oxygen existent in the water while guiding the algae growing on the water surface portion into the deep layer of the water where sufficient sunlight will not reach.
Of the foregoing measures, however, the method (1) designed to remove the nutritious substances which flow into lakes and marshes is not easy to adopt in view of the construction costs of facilities and equipment and the running costs for the maintenance thereof. Furthermore, it is impossible to completely remove the nutritious substances from unspecified polluting substances, thus making the whole scheme too difficult to be effective. Furthermore, the measure (2) to kill phytoplankton by addition of algaecides is not generally applicable because it can cause a further pollution if the water in the water area has a wide variety of applications. Furthermore, the air pumping measure (3) which forcibly pumps the water in the water area for circulation to shorten the staying period of the surface water is not effective and is considered to be inapplicable because, if the water depth is not sufficient, it will not guide algae on the water surface into a deeper water layer which the sufficient sunlight will not reach.
The present invention is designed to solve the technical problem referred to in the foregoing and the object of the invention is to provide a water polluting phytoplankton drift collecting device. The invention was conceived by taking into consideration the shortcomings of the current attempts to prevent or forestall the extraordinary proliferation of phytoplankton in the water area as mentioned above. Particularly, it is possible to prevent the proliferation of the phytoplankton in the water areas of a shallow depth from causing the water quality to deteriorate for the purpose of maintaining the water area clean.
The inventor realized that although it is impossible to completely prevent the phytoplankton from vegetating, the phytoplankton rather serves to absorb the nutrition such as nitrogen, sulfur, silica, etc. in the water flowing into water area like lakes, thereby purifying the polluted water, and intended to take advantage of it in order to accomplish the above objectives. Based on this understanding, therefore, the invention is designed to use the phytoplankton for removing the nutritious substances contained in flown-in waters instead of preventing such phytoplankton from vegetating and then, separating the water polluting phytoplankton drifts or their dormant spores to remove the same from the water.
In other words, the inventor made intensive research to come up with a device which is capable of maintaining a water area clean by absorbing and removing the nutritious substances flowing into the water area by use of phytoplankton and then collecting the water polluting phytoplankton drifts such that the scattering thereof is prevented.
As a result, the inventor conceived of a device which is inexpensive and capable of effectively functioning in shallow lakes and marshes by collecting phytoplankton drifts and its dormant spores during the winter at a predetermined place and, after collecting them, keeping them from proliferating in the water area such that the water quality is maintained in a clean state. In this connection, the water polluting phytoplankton drifts primarily means the organic polluting substances consisting of phytoplankton and its dormant spores.